One of those days.

[SSE]

Installed an RCD shower unit today, was just a case of moving existing cable from old fuse board to the unit...we'll at least that's all it was supposed to be. Basically there's two meter tails coming from top of main fuse board switch & the Earth from Earth bar in main board down to the RCD unit. I done my insulation resistance on the shower circuit before powering it up, everything was clear. Turned on RCD...bang, blew main fuse. Slight smell coming from the RCD so I assumed it was a faulty switch, put it back & got a replacement, again when I turned it on same again!! Surely not a second faulty switch??? I tested between the live & neutral contacts after I disconnected it & it was showin' 0.24 so the second switch is faulty as well, probably should have tested the second RCD before I connected it. What is the chances of this?! Is there anything else that could cause this? Bizarre.

 

[bigdavs83]

Witchcraft

 

[Deleted member 9648]

What make RCD's?

 

[R G]

Whats the make of this and the rating, also could you post a photo of the unit , could be the way its wired at the outgoing side of the rcd .....

 

[Octopus]

Got any photo's?

 

[SSE]

What make RCD's?

Proteus. The first RCD was par of the RCD shower unit, the second one was a single replacement so although it's still Proteus it's slightly different looking.

Whats the make of this and the rating, also could you post a photo of the unit , could be the way its wired at the outgoing side of the rcd .....

Proteu, 63A RCD. Afraid I've not got any photos. Everythings wired correctly, you can't go wrong, live & neutral into the top of the RCD, the live bar come out the bottom & then there's a neutral copper link from the other connection at the bottom that goes to the neutral bar. I've used about ten of these Proteus units in the last few months but never had any problem with them.

Got any photo's?

Afraid not.

 

[SSE]

It can't be the circuit as it's been tested as far as the shower switch & was clear. Shower switch has been off each time the RCD was turned on as well.

 

[Octopus]

Ze of new board?

 

[Anthony S]

Next time test the rcd before connecting the load.

 

[SSE]

Ze of new board?

Can't remember exactly, thin it was 0.26 ohms.

Next time test the rcd before connecting the load.

Yeah that's the plan first thing in the morning! Phoned one of my other mates whos a very experienced sparky, he's off the opinion it must be two faulty RCD's. It's the only explanation I cn think of but if I got put another RCD switch in tomorrow & same happens again I'm out of ideas. Well, apart from the idea of putting my foot through it!

 

[Octopus]

Can't remember exactly, thin it was 0.26 ohms.

So Ze is OK, dead tests OK - 2 faulty RCD's!!

Are you 100% sure they were connected properly?? Sounds like a dead short to me

 

[HandySparks]

Is the RCD in a metal enclosure, or plastic?

 

[R G]

If you have a spare 2 pole rcd of another make on the van try that I often have used 2 pole rcds knocking around ...
If thats o/k then get the unit replaced with another make ...

 

[SSE]

So Ze is OK, dead tests OK - 2 faulty RCD's!!

Are you 100% sure they were connected properly?? Sounds like a dead short to me

100%, no doubt whatsoever, it's only two connections, I know I can be dozey sometimes but not that dozey! It's got me puzzled that's for sure!

Is the RCD in a metal enclosure, or plastic?

Plastic.

If you have a spare 2 pole rcd of another make on the van try that I often have used 2 pole rcds knocking around ...
If thats o/k then get the unit replaced with another make ...

Possibly somewhere in that bombsite of a van yeah! Wasn't keen on trying it tonight as used last 100A fuse!

 

[Leesparkykent]

So it's popped the main fuse? And this happened when u turned the RCD on with the MCB off?